Medical Injection Device

An injection device comprising:

• a needle unit having a front needle for penetrating the skin of a subject user and a rear needle for piercing a cartridge septum,
• a medicament cartridge having a cartridge septum adapted to be pierced by the rear needle for establishing fluid communication with the cartridge interior and having a slideably arranged piston which is driveable towards the cartridge septum, the cartridge being configured for movement relative to the rear needle from a first state where the cartridge septum is sealed to a second state where the cartridge septum is pierced by the rear needle,
• a piston driver for driving the piston, the piston driver capable of being released to cause the cartridge to move relatively to the needle unit to enter into the state where the cartridge septum is pierced by the rear needle and subsequently to be moved to dispense the medicament through the needle unit,
• a holding mechanism associated with the piston driver for releasably maintaining the piston driver in an initial position, and capable of being released to allow movement of the piston driver,
• wherein the device further comprises a damping mechanism operating at least during a part of the movement of the cartridge relative to the needle unit for limiting or reducing the speed of movement of the cartridge.

An injection device comprising:

• a housing,
• a medicament cartridge having an outlet connected or connectable to a needle cannula and having a slideably arranged piston which is driveable towards the outlet, the medicament cartridge being adapted for movement relative to the housing,
• a piston driver capable of driving the piston towards the outlet of the cartridge, the movement of the piston driver defining a stroke length,
• an indicator capable of generating at least one of an audible, a tactile and a visible signal when the piston driver has travelled substantially the complete distance of said stroke length, the indicator having a deflection element which is at least partially deflected to accumulate energy during operation of the injection device and which is released to generate said at least one of an audible, a tactile and a visible signal,
• an actuator providing a stored energy source capable of being released to move the cartridge from a first position to a second position, to drive the piston driver and to deflect the deflection element, and
• an activator which upon operation releases said actuator,
• wherein the deflection element is configured for being at least partially deflected to accumulate energy prior to or during movement of the cartridge relative to the housing.